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2024 Journal article Open Access OPEN
Deep learning and structural health monitoring: temporal fusion transformers for anomaly detection in masonry towers
Falchi F., Girardi M., Gurioli G., Messina N., Padovani C., Pellegrini D.
Detecting anomalies in the vibrational features of age-old buildings is crucial within the Structural Health Monitoring (SHM) framework. The SHM techniques can leverage information from onsite measurements and environmental sources to identify the dynamic properties (such as the frequencies) of the monitored structure, searching for possible deviations or unusual behavior over time. In this paper, the Temporal Fusion Transformer (TFT) network, a deep learning algorithm initially designed for multi-horizon time series forecasting and tested on electricity, traffic, retail, and volatility problems, is applied to SHM. The TFT approach is adopted to investigate the behavior of the Guinigi Tower located in Lucca (Italy) and subjected to a long-term dynamic monitoring campaign. The TFT network is trained on the tower's experimental frequencies enriched with other environmental parameters. The transformer is then employed to predict the vibrational features (natural frequencies, root mean squares values of the velocity time series) and detect possible anomalies or unexpected events by inspecting how much the actual frequencies deviate from the predicted ones. The TFT technique is used to detect the effects of the Viareggio earthquake that occurred on 6 February 2022, and the structural damage induced by three simulated damage scenarios.Source: MECHANICAL SYSTEMS AND SIGNAL PROCESSING, vol. 215 (issue 111382)

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2024 Journal article Open Access OPEN
Seismic response and ambient vibrations of a Mediaeval Tower in the Mugello area (Italy)
R. M. Azzara, V. Cardinali, M. Girardi, C. Padovani, D. Pellegrini, M. Tanganelli
This paper describes the experimental campaigns on the Tower of the Palazzo dei Vicari in Scarperia, a village in the Mugello area (Tuscany) exposed to high seismic hazards. The first campaign was carried out from December 2019 to January 2020, and the Tower underwent the so-called Mugello seismic sequence, which featured an M 4.5 earthquake. Other ambient vibration tests were repeated in June 2021 and September 2023 when another seismic sequence struck the area near Scarperia. These tests aimed to characterise the Tower’s dynamic behaviour under ambient and seismic excitations and check the response of the Tower over time. The experimental results were then used to calibrate a finite-element model of the Tower and estimate its seismic vulnerability. Several numerical simulations were conducted on the calibrated model using the NOSA-ITACA code for nonlinear structural analysis of masonry buildings. The dynamic behaviour of the Tower subjected to a seismic sequence recorded in 2023 by a seismic station at the base was investigated by comparing the velocities recorded along the Tower’s height with their numerical counterparts. Furthermore, several pushover analyses were conducted to investigate the collapse of the Tower as the load’s distribution and direction varied.Source: JOURNAL OF CIVIL STRUCTURAL HEALTH MONITORING
Project(s): PiattafoRma open-sourcE orientata ai digital twins: tecniche di digitalizzazione 3D, monitoraggio delle Vibrazioni e mOdellazione agli eLementi finiti per la valUTazione dello stato di conservazIone di edifici stOrici e iNfrastrutture civili

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2024 Conference article Open Access OPEN
Vibration monitoring of historical towers: new contributions from data science
Girardi M., Gurioli G., Messina N., Padovani C., Pellegrini D.
Deep neural networks are used to study the ambient vibrations of the medieval towers of the San Frediano Cathedral and the Guinigi Palace in the historic centre of Lucca. The towers have been continuously monitored for many months via high-sensitivity seismic stations. The recorded data sets integrated with environmental parameters are employed to train a Temporal Fusion Transformer network and forecast the dynamic behaviour of the monitored structures. The results show that the adopted algorithm can learn the main features of the towers’ dynamic response, predict its evolution over time, and detect anomalies.Source: LECTURE NOTES IN CIVIL ENGINEERING, vol. 514, pp. 15-24. Naples, Italy, 21-24/05/2024

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2024 Conference article Open Access OPEN
Leveraging advanced numerical calibration to filter out temperature effects on vibration-based monitoring data: application to the Mogadouro clock tower
Barontini A., Pellegrini D., Testa F., Girardi M., Masciotta M., Mendes N., Padovani C.
This study investigates the advantages of integrating physics knowledge to enhance traditional data-driven methods for damage detection and early warning in a monitored structure. The implemented method combines the ability to predict variations in modal properties (such as natural frequencies) under changing temperatures, using a highly reliable Finite Element (FE) model calibrated to the experimental response of the structure, with a robust anomaly detection strategy to process new monitoring data and classify it as damaged or undamaged. The relationship between temperature and modal properties, as evaluated through the FE model, is used to normalise the monitoring data. This process filters out the effects of the environmental variation, potentially magnifying the effects of damage, which are then investigated through machine learning algorithms for classification purpose. The procedure is validated by analysing a real case study, the Mogadouro clock tower in Portugal. Several scenarios of available knowledge during the training of the damage detection strategy are simulated, discussing advantages and identifying areas for future improvement.

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2023 Journal article Open Access OPEN
Dynamic Behaviour of the Carillon Tower in Castel San Pietro Terme, Italy
Azzara Rm, Girardi M, Padovani C, Pellegrini D
This paper presents the experimental investigations conducted on the carillon tower of the Santissimo Crocifsso Sanctuary in Castel San Pietro (Bologna, Italy) and the analysis of data collected by using velocimeters and accelerometers installed on the structure. The main goal is to assess the effects of the swinging bells on the dynamic behaviour of the tower. The paper's novelty relies on the kind of structure monitored and the originality of the experiments. The structure is a rare example of a carillon tower, with fifty-five bells of different sizes, subjected to a careful measurement campaign never carried out before. Six experiments were conducted selectively by activating the bells to measure the tower's response induced by different vibration sources and determine the peak velocities recorded by using instruments at different heights. Two ambient vibration tests complemented the six experiments. The carillon's action induces low velocities on the tower, while experiments involving the bells swinging in the upper chamber produce the highest velocity values in the swinging direction; these values are more significant than those induced by the carillon alone. The most robust action is induced on the tower when all the bells (carillon plus swinging bells) ring. The experimental results are complemented by numerical simulations of the dynamic behaviour of the tower subjected to the action of a swinging bell.Source: STRUCTURAL CONTROL AND HEALTH MONITORING

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2023 Other Unknown
Analisi del collasso di strutture ad arco in muratura: indagini sperimentali su modelli in scala
E. Casassa, (relatori: Barsotti R., Barsi F., Girardi M., Padovani C., Bennati S. )
La tesi vuole analizzare il comportamento sperimentale di modelli in scala di arco sottoposti a carichi pseudostatici incrementali. I modelli degli archi sono ottenuti accostando, a secco, i conci ottenuti attraverso una stampante 3D. L'azione sismica viene simulata come una forza statica d'inerzia, proporzionale alla massa. In questo senso, per applicare un pattern di carichi adeguato è stata prevista la costruzione di una tilting table. I risultati sperimentali, raccolti sottoforma di moltiplicatori dei carichi orizzontali di collasso , vengono successivamente analizzati criticamente confrontandoli con i risultati teorici (trovati attraverso il teorema cinematico) ed i risultati forniti dal software di calcolo NOSA-ITACA.

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2023 Other Restricted
Monitoraggio dinamico di ponti mediante reti wireless di sensori
Marra Am, Morano G, Nicese B, Salvatori L, Spinelli P, Girardi M, Padovani C, Pellegrini D
Report finale del progetto "Monitoraggio dinamico di ponti mediante reti wireless di sensori" (MOODWISE).

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2023 Other Restricted
Progetto REVOLUTION - Piattaforma open-source orientata ai digital twins: tecniche di digitalizzazione 3D, monitoraggio delle vibrazioni e modellazione agli elementi finiti per la valutazione dello stato di conservazione di edifici storici e infrastrutture civili
Pellegrini D, Girardi M, Gurioli G, Padovani C
Report tecnico scientifico n.1 (attività svolta nel periodo 15 febbarioi 2022 - 15 febbraio 2023).

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2023 Journal article Open Access OPEN
Experimental investigations and numerical modelling: a fruitful interaction for the nonlinear dynamical analysis of masonry structures
Azzara R. M., Girardi M., Padovani C., Pellegrini D.
This paper describes the experiments carried out on a medieval masonry tower in the historic centre of Lucca and some finite element numerical simulations of the tower's experimental response. The Guinigi Tower, one of the most iconic monuments in Lucca, has been continuously monitored by high-sensitive seismic stations that recorded the structure's response to the dynamic actions of the surrounding environment. The monitoring campaign results have been analysed to show the effectiveness of dynamic monitoring as a valuable source of information on the structural properties of the tower. The dynamic analyses of the tower and the surrounding palace subjected to some seismic events recorded during the experiments have highlighted the capabilities of experiment-based finite element modelling. The calibration of the finite element model and the numerical analysis have been carried out by resorting to procedures developed at ISTI-CNR and able to consider the nonlinear behaviour of masonry materials.Source: Continuum mechanics and thermodynamics (Internet) (2023). doi:10.1007/s00161-023-01264-2
DOI: 10.1007/s00161-023-01264-2
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2023 Journal article Open Access OPEN
Effects of temperature variations on the modal properties of masonry structures: an experimental-based numerical modelling approach
Pellegrini D., Barontini A., Girardi M., Lourenço P. B., Masciotta M. G., Mendes N., Padovani C., Ramos L. F.
Long-term ambient vibration monitoring campaigns show that environmental parameters (such as temperature, humidity, wind speed and direction) can influence the structures' static and dynamic behaviour. In particular, thermal variations can affect the modal characteristics of ancient masonry constructions. This work presents a procedure combining experimental and numerical steps to monitor, assess and model the dynamic behaviour of masonry structures subjected to thermal loads. The procedure is tested and validated through two numerical examples and the simulation of a full-scale masonry structure, the Mogadouro clock tower in Portugal, monitored with accelerometers and temperature and humidity sensors.Source: STRUCTURES, vol. 53, pp. 595-613

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2023 Conference article Open Access OPEN
Long-term monitoring of a masonry tower with wireless accelerometers
Zini G., Marafini F., Monchetti S., Betti M., Facchini L., Bartoli G., Girardi M., Gurioli G., Padovani C., Pellegrini D.
During the last decades, significant efforts have been made to define appropriate Structural Health Monitoring (SHM) frameworks based on the vibration signatures collected by accelerometers. Data-driven approaches are increasingly adopted for damage detection through the identification of anomalies in the distribution of the frequencies. This paper analyzes the long-term monitoring data acquired from a system installed on the Matilde tower in Livorno (Italy). The tower is a historic masonry structure monitored since the end of 2018 using a wireless sensor network developed during the MOSCARDO project.

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2023 Contribution to book Open Access OPEN
Numerical modelling of historical masonry structures with the finite element code NOSA-ITACA
Girardi M, Padovani C, Pellegrini D, Porcelli M, Robol L
This chapter presents the finite element code NOSA-ITACA for static and modal analyses of masonry structures of architectural interest. NOSA-ITACA adopts the constitutive equation of masonrylike materials, which considers masonry a non-linear elastic material with zero tensile strength. The capability of modelling restoration and consolidation operations makes the code a helpful tool for maintaining historical buildings. In recent years, long-term vibration monitoring turned out to be an effective non-destructive technique to investigate the dynamic behaviour and check the health status of historical buildings. Changes in their dynamic properties, such as natural frequencies, can represent effective damage indicators. The latest NOSA-ITACA developments are oriented towards structural health monitoring. The availability of the experimental modal properties of a structure makes it possible to calibrate its finite element model via model updating procedures. In particular, the unknown structure's characteristics, such as materials' properties and boundary conditions, can be determined by solving a minimum problem whose objective function is expressed as the discrepancy between experimental frequencies and mode shapes and their numerical counterparts. Several case studies are presented to show the main features of NOSA-ITACA and its effectiveness in the conservation of architectural heritage.Source: SPRINGER INDAM SERIES (ONLINE), pp. 133-152

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2023 Conference article Open Access OPEN
Towards a cloud-based platform for structural health monitoring: implementation and numerical issues
Croce T, Girardi M, Gurioli G, Padovani C, Pellegrini D
Structural Health Monitoring (SHM) is increasingly important in protecting and maintaining architectural heritage. Its main goal is to distinguish ordinary fluctuations in a building's response from other, possibly anomalous, behaviour. SHM starts setting sensors to measure accelerations or velocities and other environmental parameters over time at fixed points of the structure. The time series processing makes it possible to perform modal tracking and damage/anomaly detection while correlating dynamical and environmental parameters. In practice, these activities are conducted separately, using different numerical codes. Thus, the idea is to take the first step to distance from such practice, leveraging the MOSCARDO system, which encompasses a Wireless Sensor Network (WSN) and a platform designed according to a cloud architecture that provides services for storing and processing data from the WSN. We employ a code based on the Stochastic Subspace Identification (SSI) technique to improve the system's capabilities, and we exploit the SSI's theoretical features to get an efficient implementation that will be integrated into the cloud-based platform. This pipeline is here presented considering data collected from a monitoring campaign on the "Matilde donjon" in Livorno (Italy) and reporting preliminary numerical results on the identification of the modal parameters.Source: LECTURE NOTES IN CIVIL ENGINEERING, pp. 610-619. Milano, Italy, 30-08/01-09/2023

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2023 Contribution to book Restricted
From structural health monitoring to finite element modeling of heritage structures - The Medieval Towers of Lucca
Azzara Rm, Girardi M, Padovani C, Pellegrini D
This chapter describes the experiments carried out on three medieval masonry towers in the historic center of Lucca, Italy. The towers have been continuously monitored by high-sensitivity seismic stations that record the structures' response to the dynamic actions of the surrounding environment. Special attention is devoted to the Guinigi Tower, one of the most iconic monuments in Lucca, whose monitoring campaign started in 2021. The goal of the chapter is to show the effectiveness of dynamic monitoring as a valuable source of information on the structural properties of the towers and sketch the capabilities of experiment-based finite element modeling.

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2023 Conference article Open Access OPEN
A digital twin-based platform for structural health monitoring: preliminary results
Girardi M, Padovani C, Pellegrini D
This paper describes the preliminary results of the REVOLUTION project, focused on designing and implementing an open-source, digital twin-based platform for the structural health monitoring of architectural buildings and infrastructures. The platform leverages several technologies, such as 2D/3D digitalization techniques, sensor networks, numerical modelling, and damage detection algorithms. Integrating such technologies will allow us to build accurate digital twins of historical buildings, monitor their dynamic properties, model their mechanical behaviour, detect damages and anomalies and plan intervention strategies.

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2023 Other Embargo
Collasso di archi in muratura soggetti a carichi orizzontali o cedimenti delle imposte
Bonuccelli N Autore, Relatori Barsotti R, Barsi F, Pellegrini D, Padovani C, Girardi M
La tesi si pone l'obiettivo di analizzare il comportamento al collasso di archi in muratura soggetti a carichi orizzontali o cedimenti delle imposte. A tal proposito sono stati eseguite numerose prove sperimentali su modelli in scala di arco montati a secco, realizzati mediante conci in materiale termoplastico. Con l'ausilio di un'apparecchiatura, denominata tilting table, viene simulata l'azione sismica come una forza statica d'inerzia, proporzionale alla massa. Per l'esecuzione della seconda tipologia di prove è stata realizzata una specifica apparecchiatura in grado di simulare il cedimento delle imposte. Dalle prove sperimentali sono stati ricavati i valori del moltiplicatore di collasso e del cedimento ultimo associati ai rispettivi meccanismi di collasso. I risultati della campagna sperimentale sono stati analizzati e confrontati con quelli ottenuti attraverso l'analisi limite. Un'ulteriore analisi numerica dei modelli è stata effettuata utilizzando il codice di calcolo agli elementi finiti NOSA-ITACA.

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2022 Journal article Open Access OPEN
The influence of deflections on the static and dynamic behaviour of masonry columns
Girardi M, Padovani C, Pellegrini D
This paper studies the influence of bending deflections on the structural behaviour of masonry columns. Some explicit solutions are presented, and the combined effects of the constitutive and geometric nonlinearities are investigated through an iterative numerical procedure. The results show that considering second-order effects affects both the collapse load and the dynamical properties of masonry beams significantly.Source: EUROPEAN JOURNAL OF MECHANICS. A, SOLIDS, vol. 94 (issue 104570)

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2022 Journal article Open Access OPEN
Dynamic monitoring of a tunnel-like masonry structure via WSN
Bartoli G, Betti M, Girardi M, Padovani C, Pellegrini D, Zini G
This paper reports an application of wireless sensor network technology to the long-term monitoring of a historic masonry tunnel-like structure located in Italy. The monitoring was performed within the activity of a research project aimed at providing a general framework to check the structural health of heritage structures and to real-time detect any potential damage that may compromise their safety. The tunnel-like structure was selected being, to the best of authors' knowledge, a challenging experiment both for the type of structure itself and for the technical solution to be employed for installing the monitoring system. This paper, after a brief description of the installed monitoring system and the design of the sensor layout, summarizes the lesson learned after one year of monitoring.Source: PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS. STRUCTURES AND BUILDINGS

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2022 Other Open Access OPEN
Dynamic behaviour of the carillon tower in Castel San Pietro, Italy
Azzara Rm, Girardi M, Padovani C, Pellegrini D
The paper presents the experimental investigations conducted on the carillon tower of the Santissimo Crocifisso Sanctuary in Castel San Pietro (Bologna, Italy) and the analysis of data collected by velocimeters and accelerometers installed on the structure. The main goal is to assess the effects of the swinging bells on the dynamic behaviour of the tower. The paper's novelty relies on the kind of structure monitored, and the approach followed. The structure is a rare example of a carillon tower, subjected to a careful measurement campaign never carried out before. Moreover, the experimental results are complemented by numerical simulations of the dynamic behaviour of the tower subjected to the action of a swinging bell.

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2022 Conference article Restricted
Structural health monitoring for architectural heritage: case studies in Central Italy
Azzara Rm, Girardi M, Occhipinti M, Padovani C, Pellegrini D, Tanganelli M
Structural health monitoring (SHM) has been recognized as a useful tool for experimentally assessing the structural behavior of historical buildings over time. If monitoring is performed continuously and for a long time, it allows to evaluate variations in the building's dynamic response to external factors. The main goal is to estimate the dynamic response of the monitored buildings to daily stresses produced by environmental and anthropogenic factors (variations in ambient temperature and humidity, wind velocity, vibrations produced by vehicular traffic or other anthropogenic noise sources including visitors, service staff, etc.) to distinguish ordinary fluctuations in the buildings' response from other anomalous behavior. Continuous monitoring also makes it possible to assess the impact of extraordinary events such as extreme weather events, earthquakes, excavations, cultural events involving many people nearby the monitored buildings. Some examples from the authors' many monitoring campaigns on monuments located in different urban environments are presented. In particular, the effect on one of the monitored buildings of the drastic reduction of seismic noise during the SarsCov2 pandemic lockdown is investigated.Source: LECTURE NOTES IN CIVIL ENGINEERING, pp. 3-12. Palermo, Italy, 4-7/07/2022

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